Read by QxMD icon Read

Markov model

Claire Guerrier, David Holcman
Binding of molecules, ions or proteins to small target sites is a generic step of cell activation. This process relies on rare stochastic events where a particle located in a large bulk has to find small and often hidden targets. We present here a hybrid discrete-continuum model that takes into account a stochastic regime governed by rare events and a continuous regime in the bulk. The rare discrete binding events are modeled by a Markov chain for the encounter of small targets by few Brownian particles, for which the arrival time is Poissonian...
October 18, 2016: Scientific Reports
Alexandra I Korda, Mariniki Koliaraki, Pantelis A Asvestas, George K Matsopoulos, Errikos M Ventouras, Periklis Y Ktonas, Nikolaos Smyrnis
The frequency of intrusive saccades during maintenance of active visual fixation has been used as a measure of sustained visual attention in studies of healthy subjects as well as of neuropsychiatric patient populations. In this study, the mechanism that generates intrusive saccades during active visual fixation was investigated in a population of young healthy men performing three sustained fixation tasks (fixation to a visual target, fixation to a visual target with visual distracters, and fixation straight ahead in the dark)...
October 14, 2016: Neuroscience
Duncan K Ralph, Frederick A Matsen
The human immune system depends on a highly diverse collection of antibody-making B cells. B cell receptor sequence diversity is generated by a random recombination process called "rearrangement" forming progenitor B cells, then a Darwinian process of lineage diversification and selection called "affinity maturation." The resulting receptors can be sequenced in high throughput for research and diagnostics. Such a collection of sequences contains a mixture of various lineages, each of which may be quite numerous, or may consist of only a single member...
October 2016: PLoS Computational Biology
G C Kabat, Wy-Y Wu, J W Bea, C Chen, L Qi, M L Stefanick, R T Chlebowski, D S Lane, J Wactawski-Wende, S Wassertheil-Smoller, T E Rohan
OBJECTIVE: The possibility that a subset of persons who are obese may be metabolically healthy-referred to as the 'metabolically healthy obese' (MHO) phenotype -- has attracted attention recently. However, few studies have followed individuals with MHO or other obesity phenotypes over time to assess change in their metabolic profiles. The aim of the present study was to examine transitions over a 6-year period among different states defined simultaneously by body mass index and presence/absence of the metabolic syndrome...
October 17, 2016: International Journal of Obesity: Journal of the International Association for the Study of Obesity
Ornella Affinito, Giovanni Scala, Domenico Palumbo, Ermanno Florio, Antonella Monticelli, Gennaro Miele, Vittorio Enrico Avvedimento, Alessandro Usiello, Lorenzo Chiariotti, Sergio Cocozza
DNA methylation is often analyzed by reporting the average methylation degree of each cytosine. In this study, we used a single molecule methylation analysis in order to look at the methylation conformation of individual molecules. Using D-aspartate oxidase as a model gene, we performed an in-depth methylation analysis through the developmental stages of three different mouse tissues (brain, lung, and gut), where this gene undergoes opposite methylation destiny. This approach allowed us to track both methylation and demethylation processes at high resolution...
October 17, 2016: Epigenetics: Official Journal of the DNA Methylation Society
Amanda A Koepke, Ira M Longini, M Elizabeth Halloran, Jon Wakefield, Vladimir N Minin
Despite seasonal cholera outbreaks in Bangladesh, little is known about the relationship between environmental conditions and cholera cases. We seek to develop a predictive model for cholera outbreaks in Bangladesh based on environmental predictors. To do this, we estimate the contribution of environmental variables, such as water depth and water temperature, to cholera outbreaks in the context of a disease transmission model. We implement a method which simultaneously accounts for disease dynamics and environmental variables in a Susceptible-Infected-Recovered-Susceptible (SIRS) model...
June 2016: Annals of Applied Statistics
Keisuke Yoshihara, Minh Nhat Le, Koo Nagasawa, Hiroyuki Tsukagoshi, Hien Anh Nguyen, Michiko Toizumi, Hiroyuki Moriuchi, Masahiro Hashizume, Koya Ariyoshi, Duc Anh Dang, Hirokazu Kimura, Lay-Myint Yoshida
We performed molecular evolutionary analyses of the G gene C-terminal 3rd hypervariable region of RSV-A genotypes NA1 and ON1 strains from the paediatric acute respiratory infection patients in central Vietnam during the 2010-2012 study period. Time-scaled phylogenetic analyses were performed using Bayesian Markov Chain Monte Carlo (MCMC) method, and pairwise distances (p-distances) were calculated. Bayesian Skyline Plot (BSP) was constructed to analyze the time-trend relative genetic diversity of central Vietnam RSV-A strains...
October 13, 2016: Infection, Genetics and Evolution
Mahsa Akhbari, Mohammad B Shamsollahi, Omid Sayadi, Antonis A Armoundas, Christian Jutten
In this paper, we propose a novel method for extracting fiducial points (FPs) of electrocardiogram (ECG) signals. We propose the use of multi hidden Markov model (MultiHMM) as opposed to the traditional use of Classic HMM. In the MultiHMM method, each segment of an ECG beat is represented by a separate ergodic continuous density HMM. Each HMM has different state number and is trained separately. In the test step, the log-likelihood of two consecutive HMMs is compared and a path is estimated, which shows the correspondence of each part of the ECG signal to the HMM with the maximum log-likelihood...
September 28, 2016: Computers in Biology and Medicine
Sylvie Deuffic-Burban, Jérôme Boursier, Vincent Leroy, Yazdan Yazdanpanah, Laurent Castera, Philippe Mathurin
BACKGROUND AND AIMS: This study quantifies the impact of different rules for access to treatment, ranging from targeted therapy in patients with ⩾F3 in Italy, ⩾ severe F2 in France, and universal therapy in UK, using noninvasive diagnostic tests of fibrosis to determine targeted therapy. METHODS: A country-specific Markov model predicts outcomes with targeted and universal interferon-free therapy vs. no treatment in the three countries. Targeted therapy was initiated in patients ⩾F2 (F2-scenario) or ⩾F3 (F3-scenario) evaluated by noninvasive diagnostic tests according to the real stage of fibrosis...
October 12, 2016: Journal of Hepatology
Phuc Le, Michael B Rothberg
BACKGROUND: The Advisory Committee on Immunization Practices recommends a single dose of herpes zoster (HZ) vaccine in persons aged 60 years or older, but the efficacy decreases to zero after approximately 10 years. A booster dose administered after 10 years might extend protection, but the cost-effectiveness of a booster strategy has not been examined. OBJECTIVE: We aimed to determine the optimal schedule for HZ vaccine DESIGN: We built a Markov model to follow patients over their lifetime...
October 14, 2016: Journal of General Internal Medicine
Zobair M Younossi, Haesuk Park, Douglas Dieterich, Sammy Saab, Aijaz Ahmed, Stuart C Gordon
BACKGROUND: New direct-acting antiviral (DAA) therapy has dramatically increased cure rates for patients infected with hepatitis C virus (HCV), but has also substantially raised treatment costs. AIM: The aim of this analysis was to evaluate the therapeutic benefit and net costs (i.e. efficiency frontier) and the quality-adjusted cost of care associated with the evolution of treatment regimens for patients with HCV genotype 1 in the United States. DESIGN: A decision-analytic Markov model...
October 2016: Medicine (Baltimore)
Giacomo Di Gesù, Tony Lelièvre, Dorian Le Peutrec, Boris Nectoux
We are interested in the connection between a metastable continuous state space Markov process (satisfying e.g. the Langevin or overdamped Langevin equation) and a jump Markov process in a discrete state space. More precisely, we use the notion of quasi-stationary distribution within a metastable state for the continuous state space Markov process to parametrize the exit event from the state. This approach is useful to analyze and justify methods which use the jump Markov process underlying a metastable dynamics as a support to efficiently sample the state-to-state dynamics (accelerated dynamics techniques)...
October 14, 2016: Faraday Discussions
N Ramaiah, Ajay Kumar
Iris recognition systems are increasingly deployed for large-scale applications such as national ID programs which continue to acquire millions of iris images to establish identity among billions. However with the availability of variety of iris sensors that are deployed for the iris imaging under different illumination/environment, significant performance degradation is expected while matching such iris images acquired under two different domains (either sensor-specific or wavelength-specific). This paper develops a domain adaptation framework to address this problem and introduces a new algorithm using Markov random fields (MRF) model to significantly improve cross-domain iris recognition...
October 10, 2016: IEEE Transactions on Image Processing: a Publication of the IEEE Signal Processing Society
Dereje W Gudicha, Verena D Schmittmann, Fetene B Tekle, Jeroen K Vermunt
The latent Markov (LM) model is a popular method for identifying distinct unobserved states and transitions between these states over time in longitudinally observed responses. The bootstrap likelihood-ratio (BLR) test yields the most rigorous test for determining the number of latent states, yet little is known about power analysis for this test. Power could be computed as the proportion of the bootstrap p values (PBP) for which the null hypothesis is rejected. This requires performing the full bootstrap procedure for a large number of samples generated from the model under the alternative hypothesis, which is computationally infeasible in most situations...
September 2016: Multivariate Behavioral Research
Pelerine Tsobgni Nyawo, Hugo Touchette
We study the large deviations of the time-integrated current for a driven diffusion on the circle, often used as a model of nonequilibrium systems. We obtain the large deviation functions describing the current fluctuations using a Fourier-Bloch decomposition of the so-called tilted generator, and we also construct from this decomposition the effective (biased, auxiliary, or driven) Markov process describing the diffusion as current fluctuations are observed in time. This effective process provides a clear physical explanation of the various fluctuation regimes observed...
September 2016: Physical Review. E
N Crampe, E Ragoucy, V Rittenberg, M Vanicat
We study a one-parameter generalization of the symmetric simple exclusion process on a one-dimensional lattice. In addition to the usual dynamics (where particles can hop with equal rates to the left or to the right with an exclusion constraint), annihilation and creation of pairs can occur. The system is driven out of equilibrium by two reservoirs at the boundaries. In this setting the model is still integrable: it is related to the open XXZ spin chain through a gauge transformation. This allows us to compute the full spectrum of the Markov matrix using Bethe equations...
September 2016: Physical Review. E
Nishant Gupta, Dale Langenderfer, Francis X McCormack, Daniel P Schauer, Mark H Eckman
RATIONALE: Patients without a known history of lung disease presenting with a spontaneous pneumothorax are generally diagnosed as primary spontaneous pneumothorax. However, occult diffuse cystic lung diseases such as Birt-Hogg-Dubé syndrome (BHD), lymphangioleiomyomatosis (LAM), and pulmonary Langerhans cell histiocytosis (PLCH) can also first present with a spontaneous pneumothorax, and their early identification by high-resolution computed tomographic (HRCT) imaging of chest has implications for subsequent management...
October 13, 2016: Annals of the American Thoracic Society
Fabiana Gatti de Menezes, Rodrigo Martins Abreu, Alexander Itria
Introduction: Secondary hyperparathyroidism (SHPT) is a consequence of chronic kidney disease. The treatment at the Brazilian Unified Heath System (SUS) is performed with calcitriol, a drug which favors hypercalcemia and/or hyperphosphatemia, hindering the control of SHPT. Another option is paricalcitol, which causes parathormone (PTH) suppression faster than calcitriol, with minor changes in calcium-phosphorus product and calcium and phosphorus serum levels. Objective: This study aims to develop a cost-effectiveness analysis of paricalcitol versus calcitriol for patients in dialytic treatment with SHPT, from the SUS perspective...
July 2016: Jornal Brasileiro de Nefrologia: ʹorgão Oficial de Sociedades Brasileira e Latino-Americana de Nefrologia
Maartje S Jacobs, Femke Kaasenbrood, Maarten J Postma, Marinus van Hulst, Robert G Tieleman
AIMS: Atrial fibrillation (AF) is the most common arrhythmia and prevalence increases with age. Patients with AF have a high risk of stroke, and screening for AF is recommended in all people aged 65 years or older to identify patients eligible for stroke prevention. A handheld, single-lead electrocardiogram (ECG) device can be used for systematic screening in the population at risk. The objective of this study is to estimate the cost-effectiveness of screening for AF in primary care with the MyDiagnostick(®) during seasonal influenza vaccination in the Netherlands...
October 12, 2016: Europace: European Pacing, Arrhythmias, and Cardiac Electrophysiology
Luis Hernandez, Shien Guo, Hector Toro-Diaz, Stuart Carroll, Syed Feisal Syed Farooq
AIMS: Peginterferon beta-1a 125 mcg administered subcutaneously every two weeks, a new disease-modifying therapy (DMT) for relapsing-remitting multiple sclerosis (RRMS), was approved in January 2015 by the Scottish Medicines Consortium. This study assesses long-term clinical and economic outcomes of peginterferon beta-1a compared with other self-injectable DMTs (interferon beta-1a [22 mcg, 30 mcg, and 44 mcg], interferon beta-1b, and glatiramer acetate 20 mg) in the treatment of RRMS, from the National Health Service and personal social services perspective in Scotland...
October 12, 2016: Journal of Medical Economics
Fetch more papers »
Fetching more papers... Fetching...
Read by QxMD. Sign in or create an account to discover new knowledge that matter to you.
Remove bar
Read by QxMD icon Read

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"